1. Field of the Invention
This invention relates to a process for preparing a medical laser knife equipped with a probe portion which generates heat.
2. Description of the Prior Art
A laser knife which has been commonly used is operated as follows. A laser beam emitted from a light source is led through an optical fiber to a probe portion made of, e.g., sapphire (.alpha.-Al.sub.2 O.sub.3) or quartz glass (SiO.sub.2) provided at the tip of the knife. Various operations such as amputation, incision, or hemostasis through coagulation are performed by light beam radiation from the probe portion with or without pressing the probe portion against the affected part or the part to be operated.
However, such a laser knife is poor in efficiency with respect to e.g., amputation or resection, because a laser beam energy is transferred to the cells, where it is absorbed and converted into a heat energy.
In my work on the invention disclosed herein I considered a possible method of improving the efficiency of the laser probe by providing a carbon coating which can convert a part of the laser beam energy into a heat energy on the surface of the probe portion of the laser knife to take incising or amputating the affected part or the part to advantage of a combination of the laser beam energy with the heat energy when incising or amputating the part to be operated on.
I applied amorphous carbon powder on the surface of the probe portion together with a binder to form the carbon coating, and then applied sapphire (.alpha.-Al.sub.2 O.sub.3) or quartz glass (SiO.sub.2) in a molten state applied on the surface of the carbon coating to form a protective coating for the purpose of preventing the combustion of the carbon powder.
However, the formation of my carbon coating and the protective coating by the above-mentioned method has disadvantages such as poor durability of the laser knife because of frequent occurrence of peeling of the coating attributable to poor adhesion between the probe portion and the carbon coating. Further, in this method, it is difficult to form a coating having a uniform thickness, which tends to cause uneven generation of heat.